Molecular devices comprising two electrodes (a bottom electrode and a top electrode) and a molecular switching layer at the junction of the two electrodes are well known. Such devices are useful, for example, in the fabrication of devices based on electrical switching, such as molecular wire crossbar interconnects for signal routing and communications, molecular wire crossbar memory, molecular wire crossbar logic employing programmable logic arrays, multiplexers/demultiplexers for molecular wire crossbar networks, molecular wire transistors, etc., and in the fabrication of devices based on optical switching, such as displays, electronic books, rewritable media, electrically tunable optical lenses, electrically controlled tinting for windows and mirrors, optical crossbar switches, for example, for routing signals from one of many incoming channels to one of many outgoing channels, etc. Typically, the molecular switching film comprises an organic molecule that, in the presence of an electrical (E) field, switches between two or more energetic states, such as by an electro-chemical oxidation/reduction (redox) reaction or by a change in the band gap of the molecule induced by the applied E-field.
It is important to form a good electric contact to the organic molecular layer in order to fabricate molecular devices. Molecules with special chemical end groups can form direct chemical bonding with metal/semiconductor electrodes to form a self-assembled layer (SAM), which can have a good electric contact with electrodes. However, the molecular layer formed on the top surface of the electrode usually has a high density of defects. If a second electrode is formed on top of the molecular layer via metal deposition methods, then an electric short can form between the first and second electrode through the defects in the molecular layer.
The formation of Langmuir-Blodgett (LB) layers employing such molecules would be preferable, because such films are known to have quite a higher density, as compared with SAM films. However, such LB films do not bond well to the electrode substrate.
Thus, there is a need for providing a high density molecular layer on a bottom electrode that also bonds well with the electrode.